OUTLINE: This is a randomized study. Patients are stratified according to presence of renal tumor (yes vs no). Patients are randomized to one of three treatment arms. Arm I: Patients receive low dose interleukin-2 (IL-2) IV every 8 hours for up to 15 doses. Treatment repeats in 7-10 days for one complete course. Arm II: Patients receive high dose IL-2 IV every 8 hours for up to 15 doses. Treatment repeats in 7-10 days for one complete course. Arm III: Patients receive IL-2 subcutaneously daily 5 days a week for 6 weeks. Treatment continues in the absence of disease progression or unacceptable toxicity. Patients with stable or responding disease receive an additional complete course of therapy.